I would like to start a serious BMO setup/tire management thread and ask that you all help us understand some of these nuances to improve performance. i know a lot is tire or chassis specific but I am not adverse to copying a race setup (or copying anything for that matter ;D) but also understand why it works. There is some good info out there but I would like to follow what the Continental GS class cars are doing because their type of road racing is closest to what I am doing during my track day events i.e. 30 minute Sprints as parts of a longer overall race day.
Plan on changing to a Eibach R2 coil over setup this winter to allow fine tuning of spring rates, ride heights and both compression and rebound damping. Want to get a feel for what rates the pros run on the tracks we all run on too, so Lime Rock, Watkins Glen, Road America, Laguna Seca, Mid Ohio, VIR, Barber, NJMP, Daytona are all on the list and info is out there, we just have to ask questions and milk our resources. This is a very mature forum which I am proud to be a part of so I think we will be taken seriously by the pros who we all talk to or do business with. They may not give out all the secrets but I bet we can get pointed in the right direction.

All input is welcome so the experienced Boss/Mustang shoes like Gary, Yellow Boss, JScheirer (hope I spelled it right) Pete, some guy named mwilson7, roketman, Arizona GT, MCM and all the others lets get it started.
Steve

Let's (for my sake) work off of this setup..it's not necessarily a GS car but is probably close to what most of you guys are running.

As an example...... 30 minute session

Random numbers from a non specific Boss 302

LF 199-198-183 RF 171-163-167
C-29 H-45 C-31 H-42

LR 184-185-189 RR 171-175-163
C-25 H-39 C-27 H-37.5

This would show a car with predominately right hand turns
The front pressures are a little high but not outrageously so but the LF needs attention.
LR looks good..perfect actually.
RR probably needs to drop a little, because the center temp is higher than the other two..but over all the pressure is a little low, not horribly so, kind of on the fence here. Might even leave it alone and address the fronts and see what happens.
RF looks like it could use a pound of two but it has the opposite problem for the RR, needs air, but overall pressure is a little too high.
Depending on how long the session last, pull 3 psi out of the LF and add 1psi to the RF and RR and recheck hot.
Now you could stiffen the rear bar, and all of this might go away, but the car was pretty neutral. Hmm maybe stiffen the compression and soften the decompression on the rt, but I'd be real careful there, you could screw yourself right out of the setup, especially on the left hand turns. That's really the engineer's call on the shocks and bar, but this is a classic tire temp/pressure dilemma.

Blacksheep what can you share about ride height settings for 275/35/18 tires? Obviously the dampers have a lot to play here but do you guys have a base height F/R (and/or L/R) that is easily measurable?

Reason I ask is my car sits a lot taller now that I took all that stuff out of it, I forgot to write down the height I had it set up at before I started :'(

I need to put the car "in the ballpark" before we start corner-balancing it. If you can't share anything I'll just eyeball it

Most racing organizations require a minimum of 4-6 inch ride height, so in order to get there you will need a set of scales, as we know most muscle cars will never get to 50/50, so with a 4 inch ride height, get the car as close as possible to 50/50, and IMO worry less about the ride height, as long as it's above the minimum.

Now there is another way to do that, (at the track) the dirt sprint car guys use "set up blocks" to get their cars to the correct height, which is real handy for you because you don't have to drag around a set of scales everywhere you go. You will need a large level or at least a straightedge and a small level. Set the car up on scales (with it level of course) then measure from the rocker panels to the ground and cut some wood blocks to the EXACT same height. Grab a handful of plywood scraps and cut small squares out of them. When you go to a track you will need to "create" a level surface using the pieces of plywood. once that is done, and the car is parked on them, then add pieces of plywood where the car was measured (these have to be even with the wood under the 4 tires, OR you can use the large level and add/subtract the distance under the measuring points to make it "level"). Then you can use the setup blocks to check ride height. It's a little crude but it works well, besides the plywood you may need some tile, or other misc thinner squares made out of different materials to create a "level" surface.

Blacksheep what can you share about ride height settings for 275/35/18 tires? Obviously the dampers have a lot to play here but do you guys have a base height F/R (and/or L/R) that is easily measurable?

Reason I ask is my car sits a lot taller now that I took all that stuff out of it, I forgot to write down the height I had it set up at before I started :'(

I need to put the car "in the ballpark" before we start corner-balancing it. If you can't share anything I'll just eyeball it

Click to expand...

Drew, setup guide for the Boss 302S comes to mind.

Here's what my car will have........all the parts are here except the rear anti-roll bar, a few grommets, nuts and bolts....Basically when I'm done I'll have a suspension equal to a Boss 302S.

I've got nothing for you guys but this is good reading so I'm subscribed.

BTW I'm going to SEMA and will post up about it later but my two main goals are to investigate coilover and brake options for our cars. If there is something specific you're looking for post up in the thread when I start it in mid October.

Drew, I was supposed to crew for a friend this weekend up at RA, but work is getting in the way!

About the springs...........

He has an early S197 with a coyote; suspension is very similar to mine, AST's vs my SACHS and a fays watts link.

Now when we setup his car we used a 300 lb/nine inch rear spring he's thinking he might be hitting the rear bump stops on high speed sweepers, turn one and turn 17 at Sebring.

He's going to use his Gopro to film the rear suspension at Road Atlanta. He's also running a gulf stream rear wing so on those turns he's getting more downforce than I'll have.

The 300 rears are what came from Ford Racing on the FR500s and that's what we had a Miller, so I'm thinking they'll be fine on my car.

Yes I know the FR500S have a rear wing but from what I've heard that wing's down force came from the weight not the aero.............

Now for your car you've got Roush (KW's?) from the TracPak car right?

Why not just start with the "stock" TracPak recommended springs? Use the Boss guide as a start and go from there?

Also I'll share any video he comes home with...........

Click to expand...

I've got the KW/Roush setup, but with softer springs in the rear. 515 fronts and 230s rear. No rear wing, just LS spoiler. With the Roush "stock" rear springs (#400), the car didn't have enough corner exit traction once I added the LCA relo brackets. I'm very comfortable with the spring bias on the car now, but if it's not performing how I want I can swap the 400s back in and try something different. Other option is to order new springs all around--but I don't think it will come to that until more serious aero gets involved.

I keep looking at pictures of the Roush 302R cars (and some others) that have relatively large wheel gaps (or taller ride height) to allow for their now very-soft springs to operate properly. I'm thinking I'm going to end up somewhere close to this, at least visually.

Again, this is in the "eyeballing it" category for now. I'll have to see how the car actually reacts once we get a baseline setup on it.

In for the info. Hope to contribute eventually. All I have right now is this satellite photo I got from a buddy at the NSA. Not sure what good it is, except to a) show ballpark cold tire temps for Pirelli slicks, and b) show what kind of record keeping we should be doing at the track.

Also setup "cheat" sheets (quick reference guides):http://www.wtrscca.org/tech.html ( I use a printed .pdf version of this in my track toolbox for quick reference)
Similar but different:
http://www.racecartuner.com/03/SuspensionCheatSheetV2.htm

I should add that another thread showed that these cars had the LCA relocation backets, but continued to run the LCA's in the stock location.
IIRC Jimmy posted that info up with pics.

Which leads to the question: These guys must be running UCA's instead to compensate for the anti squat? And presumably, they wanted roll understeer baked into the rear end for stability and what I can only presume to be driver confidence...

My notes show that the Roush UCA is 90% anti squat, and stock settings are 50% anti squat. FWIW.

The 302R cars are limited in ride height depending on the class they are running. Not knowing what I don't know, I had Capaldi set up mine. I've got the AST 4150 coil overs and have 600# springs in the front and 400# springs in the rear. The rest of the suspension is the full race setup found on the S. I am also sitting at about 4" ride height, but with the race oil pan slightly lower, I would be afraid to lower it any further for fear of catching it on something. This is the same reason I did not install the tranny cooling scoop.

I should add that another thread showed that these cars had the LCA relocation backets, but continued to run the LCA's in the stock location.
IIRC Jimmy posted that info up with pics.

Which leads to the question: These guys must be running UCA's instead to compensate for the anti squat? And presumably, they wanted roll understeer baked into the rear end for stability and what I can only presume to be driver confidence...

My notes show that the Roush UCA is 90% anti squat, and stock settings are 50% anti squat. FWIW.

Click to expand...

Be careful there--on the FRPP relo brackets, the "upper hole" is still an inch or more lower than the stock location. You want the LCAs to be angled slightly downward to the rear of the vehicle, or at least parallel to the ground, if you're not using a UCA. And from what I've read, you don't necessarily want to use a UCA that alters the geometry if you're using the relo brackets.

Be careful there--on the FRPP relo brackets, the "upper hole" is still an inch or more lower than the stock location. You want the LCAs to be angled slightly downward to the rear of the vehicle, or at least parallel to the ground, if you're not using a UCA. And from what I've read, you don't necessarily want to use a UCA that alters the geometry if you're using the relo brackets.

Click to expand...

Right - we're on the same page.
Jimmy's photos showed that the race teams used the factory position -- they didn't use any of the holes on the relo bracket.
I'll see if I can dig up the thread and bring the photos here.

I recall he even inquired about this with one of the race mechanics, and they essentially looked at him quizzically stating something to the tune of "why would I want to reduce the available grip?"...which spurred a big discussion on our forums here.

EDIT: found the pic:

Taken from thread: https://trackmustangsonline.com/index.php?topic=5902.msg89794#msg89794

So given that info, it only leads me to assume that the race teams must be playing with anti squat via the UCA, and leaving the LCA location more for tuning roll steer rather than anti squat.

Interesting enough, Capaldi set my LCA's in the exact same position/setup. Upon asking about it, Craig Capaldi said to run the car in that position first. Let us know what the car is doing and if we need to adjust, we can talk about what adjustments to make. So far I'm extremely pleased with the initial setup. Maybe when I get another few track days under my belt, I might get smart enough to tell them exactly what the car is doing, but I doubt it.